A meridian of longitude is an imaginary north–south line on the Earth's surface that connects both geographic poles. These lines are used to measure the angular distance east or west of a primary reference line known as the . Core Characteristics What is the Prime Meridian, and why is it in Greenwich?
A is an imaginary semicircle that connects the North Pole to the South Pole. Every meridian is a line of constant longitude. If you stand on any point along a given meridian, your clock time (based on the sun’s position) will be the same as anyone else on that line.
To understand meridian longitude, it is helpful to break down its two components: Longitude (
Because longitude measures distance East or West, a "Zero Point" is required. Historically, this was a source of immense confusion and political jockeying.
If Greenwich time is 12:00 noon and your local noon occurs 2 hours later, you are 30° west.